Manufacturing processes which involve the manipulation of mechanical systems are being performed with ever increasing speed. This trend is due in large part to the advent of high speed electronic control systems. Many of these mechanical systems require precision control of position or other aspects of the operation. For example, an actuator in a robotic device may create a controlled movement or other action whereby a task is accomplished. Oftentimes there may be several tasks that are completed in rapid succession.
In performing such tasks, it is often the case that the controlled motion will be imperfect in so far that it does not match the motion that was desired due to physical realities extant in each situation. For example, a robot arm might move from one position to a target position, but will not come to rest immediately at the target position. A vibration may occur as the arm flexes when attempting to stop and overshoots the target position, oscillating until it finally comes to rest. In such a situation, the actuator will in reality create imperfection in the motion.
This unwanted motion or unwanted dynamics may hinder high speed production or create problems in the operation of machines. For example, unwanted dynamics created by actuators on a system in response to a control command will cause a loss in manufacturing time as the system may be required to wait until unwanted vibration or other dynamics settle. This is commonly referred to as "settling time." In the case of manufacturing processes, unwanted movement may cause inaccuracies that translate into quality control problems. Also, inaccuracies in controlled movements may result in unnecessary wear and tear on equipment.
Consequently, there is a need for control systems that will actuate controlled motions in a manner in which unwanted dynamics are minimized or eliminated.